Communication systems are widely used in computer and device networks to communicate information between computers and other electronic devices. Transceivers of a communication system send and receive data over a link (including one or more channels) of a communication network to communicate with other transceivers. A transceiver includes a transmitter for sending information across a link, and a receiver for receiving information from a link. The receiver detects transmitted data on the link and converts the data into a form usable by the system connected to the transceiver.
In some communication systems known as wireline communication systems, the communicated data is encoded on a modulated signal which is typically transmitted differentially over a pair of wires. In such systems, the common-mode signal on the two wires does not carry any information and it is typically noise from electro-magnetic interference and crosstalk. In a perfect system, the common-mode signal is very well balanced and does not convert to a differential signal. However, in any practical system the transversal conversion loss (TCL) is finite which means some portion of the common-mode signal shows up as differential noise at the receiver input. The imbalance that would cause a finite TCL can be anywhere in the signal path including the wireline channel, the connectors at both end of the channel, and even the components that are used to detect the differential signal.
Examples of wireline communication systems that are susceptible to common-mode noise include various varieties of Digital Subscriber Line (DSL) and Ethernet over copper, such as 10GBASE-T allowing 10 gigabit/second connections over unshielded or shielded twisted pair cables. Although the information carrying signal of the system does not have a common-mode component, there are other sources that can induce a common-mode signal in the communication channel. One particularly important source of common-mode noise is radio frequency interference (RFI). The sources of RFI are abundant. Radio and TV stations, mobile phones and base stations, wireless network equipment, I-HAM transceivers, and walkie-talkies are examples of such sources. The noise from RFI may be a limiting factor in the performance of a wireline communication system.
Accordingly, what is needed are systems and methods that reject or reduce radio frequency (RF) interference in the performance of wireline communication systems, providing more robust communication in such systems.